[Dave Oxley]
We have had a deadlock issue with JGroups. The same issue affects 2.2.8 and 2.4.0. The call_stack in blocks.RequestCorrelator is a class variable and is set when a message is processed in util.Scheduler with deadlock_detection set to true. However if multiple threads call sendRequest in blocks.RequestCorrelator then they pick up the call_stack that may not be relevant to that request. This is most evident when concurrent_processing is also set to true as the call_stack grows permanently. The attached patch (against the 2.4 branch) makes call_stack a ThreadLocal and is set by the util.ReusableThread used to process the request. I've also changed the setConcurrentProcessing methods so that they work after the various objects have already been constructed.